# Open source quality is not guaranteed.
Whereas close-source is? The bug-free Microsoft OSes is the obvious shining example of that I guess.

# There is no standard open source license. The Open Source license is not a commercial contract and this may mean that the user is exposed to some legal risks.
No license is a contract. It is a license. As you point out there are as many close-source licenses as there are close-source companies. At least in the OSS there is one license much more common than others.

# Open source does present some legal risks.
# Legal Indemnification.
I'll take these together. Read all of the closed-source click-through licenses that you agreed to when installing all of your windows software (assuming that you use it ... take someone elses if you don't). Count the number of times that those click-throughs disclaim any responsibility or liability. Count the number of times that they offer indemnification. What is that you say? You can see no mention of indemnification in any of them? Shocked, I say shocked!

# Vendor support.
Have you ever actually tried to get support from a software company? In my experience the user community is the best place to look for help. Bean-counters and lawyers like a safety net, sure, but you can get that in the OSS world too ... an expensive contract with someone that you never use because they are mostly clueless.